/*
 * Created on 19-Dec-2005
 * Created by Paul Gardner
 * Copyright (C) Azureus Software, Inc, All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

package org.gudy.azureus2.core3.disk.impl;

import java.util.ArrayList;
import java.util.List;

import org.gudy.azureus2.core3.util.AEMonitor;

public class DiskManagerAllocationScheduler {
    private List instances = new ArrayList();
    private AEMonitor instance_mon = new AEMonitor("DiskManagerAllocationScheduler");

    public void register(DiskManagerHelper helper) {
        try {
            instance_mon.enter();

            instances.add(helper);

        } finally {

            instance_mon.exit();
        }
    }

    protected boolean getPermission(DiskManagerHelper instance) {
        try {
            instance_mon.enter();

            if (instances.get(0) == instance) {

                return (true);
            }

        } finally {

            instance_mon.exit();
        }

        try {
            Thread.sleep(250);

        } catch (Throwable e) {

        }

        return (false);
    }

    protected void unregister(DiskManagerHelper instance) {
        try {
            instance_mon.enter();

            instances.remove(instance);
        } finally {

            instance_mon.exit();
        }
    }
}
